Shock absorber



May 26, 1931. A. w. F. MANZEL SHOCK ABSORBER Filed Feb. 19, 1927 2Sheets-Sheet l May 26, 1931. A. w. F. MANzEl.

SHOCK ABSORBER Filed Feb. 19, 1927' 2 Sheets-Sheet 2 Halal/vla iff.'MaJ/156%, Indnor.

Patented May 26, 1931 UNITED STATESl PATENT OFFICE AnoLPH w. r. MANzEL,or BUFFALO, NEW Yoan, AssIGNoR 'ro MANzEL sitos. co., or

BUFFALO, NEW Yoax, A CORPORATION or NEW vom:

SHOGK ABSOBBER Application led February 19, 1927. Serial No. 169,535.

' My invention relates to shock absorbers for cushioning the movement oftwo relatively movable members, and more particularly to that type ofshock absorber in which oil or some other suitable fluid controls theaction of each of said relatively movable membersin one direction whilea spring of suit able power governs the relative movement of each ofsaid members in an opposite direction; the invention being especiallydesigned for use on automobiles or other vehicles and adapted to checkthe rebound of the vehicle body when the vehicle 4passes into a rut orover a projection in the road.

The primary object of myinvention to provide a shock absorber in whichprovlslon is made for more eiiectivelyresistin the shocks to which theautomobile is subjected when passing over rough roads, and to controlthe iow of the resistingfluid within the shock absorbers in a moreeffective manner than has heretofore been possible.

A further object of my invention is to provide a shock absorber inwhich'the iiuid control mechanism is constructed so as to guard againstthe clogging of oil passages within the casing -of the shock absorbersvand to simplify the construction of shock absorbers of this type.

Inthe drawings: y

Fig. 1 is a sectional elevation of a portion of a car showing tlEmannerof applylng this improved shock absorber thereto.

Fig. 2 is a central vertical longitudinal section through the lshockabsorber.

Fig. 3 is a horizontal section-taken on line 3 3, Fig. 2.

Fig. 4 is an enlarged transverse section taken on line L1--4, Fig. 2,looking in the direction of the arrow crossing said line.

Fig. 5 is an enlarged transverse section taken on line 5 5, Fig. 2,looking in the direction of the arrow crossing said line.

Fig. 6 is an enlarged horizontal section i taken on line 6--6, Fig. 2.

Fig. 7 is a detached perspective view of the vadjustable control valvewhereby the passage of oil or other fluid being used 1n the shockabsorber from one chamber to the other,

5 is controlled.

Fig. 8 is a detachedperspective view of the guide sleeve co-acting withsaid control valve.

Fig. 9 isa detached perspective view of the relief valve.

Fig. 10 is a detached perspective v iew of the combined relief valveguide and seat.

Fig. 11 is a vertical longitudinal section of the lower end of a shockabsorber, showing a slightly modified-form of my invention.

Fig. 12 is an enlarged transverse vertical section taken on line 12-12,Fig. 11.

Fig. 13 is a cross section through therelief valve stem shown in Figs.11 and 12.

Fig. 14 is a detached perspective view of the relief valve shown inFigs. 11 and 12.

In Fig. 1, I have shown the parts of an automoblle Vto which one of myvimproved shock absorbers is shown applied, and as illustrated theseparts are at the front of the automobile. It is, however, to beunderstood that a shock absorber is provided at each side of theautomobile or other vehicle, and that 'a pair of shock absorbers may beused at the front or at the rear, or both at Vthe front and the rear ofthe automobile.

The Vreference numeral 15 designates the frame or chassis of anautomobile and 16 one of the leaf springs fastened at opposite ends tosaid frame or chassis in the usual manner,.and between its ends to anaxle 17, which is shown in cross section in Fig. 1.

When passing into a rut in the road the leaf spring becomes flexed,opposite ends of the spring being forced closer to the road surfaceunder s r1ng pressure, with the result that the` y of the automobileconnected to the ends of the sprin is drawn downwardly. The tendency othe spring to recover after passing over the rough portion or portionsofthe road will cause a violent upthrow of the body of the automobile,particularly when traveling at a high rate of speed, and thus causingundue strain on the spring. The body or the chassis and the spring orthe axle may be considered as two relatively movable parts, to one ofwhich the housing or casing of the shock absorber is secured, and to theother an element extending from said housing or casing and adapted toactuate parts within said casing to which said extending element isconnected.

The housing or casing of the shock absorber is designated by the numeral18, and it is divided into two chambers 19, 20, by a wall 21, one sideof which is curved transversely to form part of the chamber 19, which iscylindrical and serves as a plunger cylinder. The chamber may be of anydesired formation in cross section.

The wall 21 is thickened along a portion of yits length to provide acontrol chamber 22,

the lower end of which is spaced from the bottom of the chamber 20 andthe upper end arranged. in a plane a considerable distance beneath theupper end of the wall 21. Arranged vertically in this control chamber isa vertical passage 23, which is screwthreaded along its length at twopoints and of different diameters, and connecting this vertical passage23 with the cylinder -19 is an oil passage or port 24 with which isaxially alined a screw-threaded opening 25 extending from the exteriorof the control 'chamber to the vertical passage 23. This verticalpassage has its greatest diameter at its lower end so as to form a mainvalve chamber 26 which extends from a point at least in line with thehighest point of the passage 24 to the lower end of the control chamber22. The lower end of the vertical passage 23 is screw-threaded, as at27, and has screwed thereinto a valve seat in the form of a sleeve nut28, the upper end of the passage through said sleeve nut, or valve seat,being flared, as at 29.

From the upper end of the main valve chamber 26 the vertical passage isreduced 111 diameter upwardly to form a relief valve chamber 30, thelower end of which is screwthreaded and has threaded thereinto a.- valvestem guide 31 in the form of a sleeve provided at its lower end with anoutwardlyextending flange 32 adapted to bear against the top wall of themain valve chamber 26 when said guide sleeve is threaded upwardly intothe relief valve chamber to its full extent.

At thelower end of the guide 31, or guide sleeve as it may be termed, anannular depending flange 33 is arranged around which the upper end of acompression sprmg 34 1s placed, said spring being interposed betweensaid guide sleeve and a spherical or ball valveL end of said sleeve.That portion of the cylindrical body of said valve extending above theflange 39 is surrounded by the lower end of a compression spring 40,said end bearing against the flange 39 and keeping the latter seatedfirmly against the upper end of the valve stem guide sleeve 31, whilethe upper end of said spring bears against a shoulder 41 formed in thevertical passage 23 by reducing the upper end thereof. The outstandingflange 39 is notched, preferably at diametrically opposite points, as at42, the notches so provided serving as oil passages when the reliefvalve 38 rises from its seat.

The valve stem guide sleeve 31 is slotted longitudinally, as at 43, theslots extending from' the upper end of said sleeve downwardly a distancesomewhat less than the lengthof the body portion of the relief valvefrom its flange 39 to its lower end, so that when the valve is depressedby the spring 40, the body portion of said valve will completely coverthe slots 43 of said guide sleeve, thus preventing the escape of any oilupwardly through the control chamber, except under pressure suflicientto compress the spring 40, which will allow the valve 38 to r1se anduncover portions of the slots 43. These slots serve as oil passages andthe degrec to which they are uncovered will be in accordance with thepressure of the oil exerted against the lowerend of the relief valvewithin the valve stem guide sleeve. This, of course, will also result inthe flange 39 being lifted out of contact with the upper end of saidvalve stem guide sleeve so that the oil escaping upwardly through theslots or passages 43 will enter the space between the upper end of saidguide sleeve and said flange 39, and escape through the notches orpassages 42 in said flange, this oil finally passing upwardly throughand around the spring 40 and'out the reducedupper end of the verticalpassage in the control chamber 22. Such displacement of the relief valvewill, however, not be allowed until other parts of the device, to bepresently described, have reached their functioning limit or becomeaccidentally defective in operation.-

All of the parts within the control chamber are introduced thereintofrom the bot.- tom of said chamber, and to admit of this, the bottom ofthe oil-containing casing 18 is provided with a screw-threaded opening44 of greater diameter than all of the parts fitted or placed into saidcontrol chamber, and as illustrated in Fig. 2, the part having greatestdiameter or transverse dimension is the valve seat 28. Thisscrew-threaded opening 44 is closed in an oil-tight manner by a screwplug 45 between the head 46 of which and the under side of the bottomwall of the casing 18 a washer 47 is interposed.

In assembling the parts within the control chamber the relief valve 38is placed into the valve stem guide sleeve 31 from the upper endthereof, and the spring 40 mounted von the outstanding flange 39 of saidvalve. v The three parts so assembled are introduced through thescrew-threaded opening 44 in the bottom of the casing after removing theplug 45, and by means of a suitable tool en.- gaging, for example, toolslots 48 in the lower end of the valve stem guide sleeve, the latter isthreaded upwardly into the relief valve' chamber 30 until the flange ofsaid guide sleeve is in firm contact with the top wall of the main valvechamber 2 6. f

With lthe parts constituting the relief valve mechanism in place, thespherical ball valve 35 is placed against the valve seat 28 and thecompression spring 34 against the spherical or ball valve, and thesethree parts are then introduced through the screw-threaded opening 44and the valve seat threaded into the lower threaded end of the. valvechamber 26 until the outstanding flange 36 of said valve seat is in firmcontact with the under side of the control chamber 22. When the partsare properly.. arranged, the upper end ofthe spring 34 will surround thedepending flange 33 of the valve stem guide sleeve 31 and bear againstthe outwardly-extending flange 32 of said guide sleeve, while the lowerend of said spring will be in firm Contact with the spherical or ballvalve 35 and keep the same firmly seated against the flared portion 29of 4said valve seat.

The threaded opening 25 in the side of the control chamber has thereduced inner end' of a control valve guide sleeve 49 threadedthereinto, said guide sleeve having an axial bore of even diameterthroughout its length and having its cylindrical wall slotted, as at 50,the slots extending inwardly from the outing a stuffing box 53 isprovided. An adjustable control valve 54 is passed through said stuffingbox and threaded through said opening 52, the inner end of said valvebeing reduced in diameter to enter the valve guide sleeve 49 from itsouter end so as to cover or close the slots or passages in said guidesleeve to any desired degree, depending 011 the adjustment made for saidvalve.

As clearly shown in Figs. 2 and 3, this valvev is adjusted so that theinner end thereof terminates a very slight distance from the inner endsofthe slots or passages 50 in the valve guide sleeve, thus providingvery small openings through which oil may pass between the ends of saidslots and the inner end of said valve.

Within the chamber or cylinder 19 a plunger or piston 55 is arranged forreciprocable movement, its lower end being reduced in diameter to forman abutment for the upper end of a comparatively powerful spiral spring56, the upper portion of which surrounds the reduced portion" of theplunger or piston, while'the lower end thereof bears against the bottomwall of said chamber or cylinder.

The screw plug 45, while permitting the introduction ofthe certain partswithin the control chamber, is also adapted for draining the oil chamber20, and a screw plug 57 is threaded into a threaded opening 58 formed v'in the bottom wall of the chamber or cylinder 19 for the purpose ofconveniently draining the same. A

The .upper face of said plunger or piston 55 is provided with adepression 59 in which is placed a hardened wear plate 60 somewhatthinner than the depth of said, depression so that the upper surface ofthis wear plate is in a plane beneath the upper edge of the surroundingwall of said depressions. A comparatively shallow 'pocket 61 istherefore provided above this wear plate in which oil is retained.

Projecting from the casing 1.8 are securing lugs 62 by means of whichthe casing may be fastened to the frame or chassis of the vehicle,suitable bolts or other fastening means being provided for the purpose.

Extending transversely through the casing is a rock shaft 63, which ispreferably integral with a crank or actuating lever 64 extending fromone end of said shaft at right angles thereto, and substantiallyparallel with the frame or chassis of the automobile. rl`hat portion ofthe rock shaft positioned between t-he two-side walls of the casing 19has an actuating arm 65 secured thereto, the outer .end of which isprovided with a rounded contact portion 66 into which is fitted ahardened wearing pin or other element 67 which rides in contactwith thehardened wear plate 60 in the upper end of the piston or plunger 55. Astrip of webbing or other flexible material 68 is secured at one end tothe free end of said actuating lever 64, and it has its other endfastened to the axle 17 in any approved manner.

The top wall of the casing is preferably in the form of a removablecover 69 fastened to the body of the casing by means of bolts 70,

or otherwise, and in this top wall is a fillingv opening 71 throughwhich oil or other fluid,

used within the casing, is to be poured, this filling opening beingclosed with a screw plug 72 When the automobile to which the device isapplied travels over" uneven roads, passes over ruts, or strikes anobstruction, the chassis and body of the automobile will lower, due toits being supported by the springs 16, which become flexed the resultbeing that the casing moves downwardly with the body of the automobileand positions the actuating lever 64 at an angle to the horizontal. Thiscauses the actuating arm 65 to assume a similar position, in whichposition the free end of said actuating arm more closely approaches thecover 69 of the casing. This allows the spring 56 in the cylinder orpump 19 to force the plunger or piston 55 upwardly, thereby creatingsuction within the lower portion of the cylinder, also within the oilpassage 24 and the valve chamber 26; thus causing the spherical orlballvalve 35 to be lifted from the valve seat 28 against the action of thecompression spring 34. This results in oil being drawn upwardly fromtheybottom of the chamber 20 through the valve seat 28, valve chamber26, oil passage 24, and into the chamber or cylinder 19. Under suchaction the fluid in thechamber 20 is lowered, and lling of the enlargedunoccupied portion of the cylinder 9, by reason of the elevation of thepiston 55,.takes place. y

When the chassis and the body of the vehicle move upwardly on what isgenerally termed the re-bound the casing 18 will move upwardly with thechassis or body, the free end of the actuating lever 64 being restrainedfrom upward movement due to the fact that it is connected by the webbing68 with the axle 17. This causes the actuating lever 64 to graduallyassume a horizontal position, or a less inclined or angular position,and at times even an oppositely inclined or angular position, dependingin the first instance on the position of such lever when the parts arenormal. However, as shown in the drawings, the lever is substantially inhorizontal position when the parts are normal and consequently afterassuming a rearwardly inclined position when the body lowers and thespring is flexed, recovery of the body to normal position will returnsaid lever to horizontal position, at which time the actuating arm willagain assume the position shown in Fig. 2, having caused the plunger orpiston 55 to be depressed against the force of the main spring 56.During the downward movement of the plunger or piston within itscylinder, oil within said cylinder is forced outwardly from the lowerportion thereof into the valve chamber 26, and as the spherical or ballvalve was seated against its valve seat by the spring 34 the instant thepiston reached the end of its upward movement, the oil forced into thevalve chamber 26 by action of said plunger or piston will be com elledto find an outlet from the valve cham er 26 in some other direction, andfor this purpose the adjustable control valve 54 and the guide sleeve 49are provided, the oil passing into said guide sleeve and escapingthrough the small openings provided between the ends of the slots insaid guide sleeve and the inner end of the reduced portion of saidvalve. These small openings are restricted to the required size throughthe adjustment of the control valve 54 within its guide sleeve, and asthese openings are comparatively small, the oil escapes therethroughslowly and a slow recovery of the parts takes place without subjectingthe occupants of the automobile to Jar. This control valve 54 may beadjusted according to the weight carried by the springs of theautomobile, but in all instances a slow escape of oil takes place sothat the rebound of the body of the automobile is effectively checkedand said body allowed to return gradually and slowly to normal position.

In the event that the valve-controlled openings in the guide sleeve 49become clogged or the pressure within the valve chamber 26 becomesexcessive, the oil within said chamber acts against the under side ofthe relief valve 38, which is lifted under the pressure exerted andunseats the outstanding flange 39 thereon from the upper end of thevalve stem guid sleeve 31, and atv the same time uncovers t e lower endsof the slots in said valve sleeve, during which action the compressionspring 41 becomes compressed. This .results in the oil under excesspressure being directed upwardly through the slots 50 of the valve stemguide sleeve, through the notches 42 in the flange 39 of the reliefvalve, and causes the oil to escape out into the chamber 20 from theupper end of the control chamber 22.

In Fig. 11, a modified form of relief valve, under the principleinvolved, is shown. In this instance the upper portion of the controlchamber is only slightly decreased in diameter and a cylindrical valvecasing 73 fitted thereinto, said valyve casing being inserted xfrom thebottom of the control chamber before positioning the valve seat 28, thespherical or ball valve 35, and the expansion spring 34 within the valvechamber 26. This valve casing 73 is provided with an axial bore 74 oftwo different diameters to form an up wardly-.facing shoulder 75. Thesmaller portion of the bore, designated by the numeral 76, serves as avalve stem guide. and the larger portion 77 as a spring chamber.

In the preferred construction, best shown in Figs. 2 and 4, the stem ofthe relief valve is solid and the valve stem guide provided with oilpassages adapted to be covered or uncovered by said solid valve stem,whereas in t'he modification shown in F ig. 11, the valve stem guide 76ofthe cylindrical valve casing is devoid of oil passages and the reliefvalve des` ignated, in this instance, by the numeral 78, is soconstructed that when lifted by oil pressure from beneath, it' willfurnish the nec.

essary oil passages. For this purpose, this relief valve has its stem.79 slidably fitted within the smaller portion of the bore or valve stemguide 76', and the upper portion of this stem is reduced in diameter, asat 80, at the upper end of which reduced portion an outstanding flangeor head 8l is`provided which bears agaiinst the. upwardly-facingshoulder 75 formed in the bore 74 of the cylindrical valve casing.

Like the outstanding flange 39 of the auxiliary or safety valve 38 inthe preferred construction, this flange or head 81 also has notches 82at diametrically opposite points. The stem of this auxiliary or safetyvalve 78 extends downwardly into the valvel chamber 26, and atdiametrically opposite points has grooves 83 formed longitudinallytherein, each of these grooves being'deepened from their upper endsdownwardly to the lower end of the valve stem, as best shown in Figs. 12and'14.

Within the larger portion or spring chamber 77 of the cylindricalvalve'casing 73, is a compression spring 84, which bears at its upperend 'against the top wall of the control chamber 22, and at its lowerend against the top of the relief valve 78, or more particularlyagainst' the upper face of the head'81 of said valve. This modified formof relief valve mechanism operates as follows:y

When for any reason the escape openings in the valve guide sleeve 49become clogged, or the pressure within the valve chamber 26 becomesexcessive, or in other words, when the pressure becomes greater thanallowed for by the retardedescape of the oil through the valve guidesleeve 49, vthe oil within said chamber 26 exerts its pressure upwardlyagainst the lower end of the relief valve 78,v

with the result that this valve is lifted against the action of thecompression spring 84. The oil, of course, is forced upwardly into thegrooves at opposite sides, of the stem of this valve, and when saidvalve is raised to bring the upper ends of the grooves above theupwardly facing shoulder 75, the oil will pass into the spring chamber 7.7, escaping upwardly through the notches 82 formed in the head of saidvalve and thence out through the top of the control chamber 22. It is,of course, understood thatl the portion of the relief valve chamber 30in the preferred construction, which may also be termed a springchamber, and the spring chamber 77 in the modified construction, will befilled with oil so that' the exact quantity of oil forced into thesespring chambers from the bottom thereof will be displaced at the upperend of the control chamber and will be delivered into the oil chamber20.

Having thus described my invention, what I claim is 1. A shock absorber,comprising a casing having an oil-containing chamber and a cylinder, avalve-controlled chamber within said oil-containing chamber at one sideof said cylinder, a plunger Within said cylinder, a spring-pressed valvewithin said valvecontrolled chamber normally closed to prevent theadmission of oil into sai-d valvecontrolled chamber from said oilchamber and the escape of oil from said cylinder into saidoil-containing chamber during the pressure stroke of said plunger, saidvalve opening to admit oilfrom said oil-containing chamber to saidcylinder 'during the suction stroke of said plunger, and a definitelyrestricted oil passage leading from said valvecontrolled chamber to saidoil-containing chamber and allowing the passage of fluid therethroughunder impeded flow during the pressure stroke of said piston.

2. In a shock absorber, comprising an oilcontaining chamber, a cylinder,a valvechamber between the oil-containing chamber and said cylinder, aplunger within said c linder, a passage leading from said cylin er tosaid oil-containing chamber and having a deiinitely vrestricted oilpassage opening into said oil-containing chamber yto provide impededflow of oil from said cylinder to said oil-containing chamber during thepressure stroke of said plunger, a valve within said valve-chamber toallow a free low of oil from said oil-containing chamber to saidcylinder during the suction stroke of said plunger, and means incommunication with 'said valve-chamber serving as *a relief to allow thepassage of oil from said cylinder to said oil-containin chamber whenpressure created by sai plunger becomes excessive.

3. A shock absorber, comprising a casing adapted to be secured to one oftwo relatively movable parts and having an oil-containing chamber and acylinder provided with an extension projecting into said oilcontainingchamber and spaced from the bottom thereof, a valve chamber in saidextension, a passage leading from said valve chamber to said cylinder, adefinitely restricted passage leading from said valve chamber to saidoil-containing chamber, an inlet for said valve chamber opening throughthe bottom of said extension into said oilcontaining chamber, aspring-pressed valve closing saidI inlet, a relief passage connectingsaid valve chamber with said oil chamber, a spring-controlled reliefValve within said relief passage, a plunger within said cylinder, aspring effecting the suction stroke of said plunger, an actuatoreffecting the pressure stroke of said plunger, and means connected withsaid actuator adapted to be connected to the other of said tworelatively' movable parts.

4. In a shock absorber, an oil-containing chamber and a cylinder, aplunger within said cylinder, a valve normally closed and allowing thefree flow of oil from said oilcontaining chamber to said cylinder, and acontrolled oil escape comprising a sleeve having one end in connectionwith said cylinder and being provided in its wall with alongitudinally-elongated opening and an adjustable control valve fittinginto the opposite end of sai-d sleeve and providing a I definitelyrestricted passage in said longitudinally-elongated opening fortheimpeded passage of oil from said cylinder to said oilcontaining chamberduring the pressure stroke of said piston.

5'. In a shock absorbertwo oil-containing chambers, a control deviceproviding for the impeded flow of oil from one of said chambers to theother, comprising a sleeve-like element having one end opening to one ofsaid chambers and projecting into the other chamber, the projectingportion having slots at diametrically opposite points extending from theprojecting end of said sleeve inwardly, and an element fitted into saidsleeve from said projecting end and terminating a distance from theinner ends of said slots to provide restricted oil passages in saidsleeve.

6. A shock absorber, comprising a casing having an oil-containingchamber and a cylf inder, a plunger within said cylinder, avalvecontrolled passage leading from said oil-containin chamber to saidcylinder, a sleevelike e ement 'screw-threaded with one end into thewall between said oil-containing chamber and said cylinder, saidsleeve-like element having its inner end connected with saidvalve-controlled passage between the valve thereof and said cylinderandextending into said oil-containing chamber, said sleeve-like .elementhaving an elongated longitudinally-disposed opening therein, and anadjustable valve ittin into the extending portion of said sleeve-1i eelement and terminating within the latter a definitely spaced distancefrom the inner end of said opening, said adjustable valve beingadjustable lengthwise within said sleeve-like element from the exteriorof said casing.

7. A shock absorber, comprising a casing having an oil-containingchamber and a cylinder separated by a wall provided with a portionextending into said oil chamber and serving as a control chamber, aplunger within said cylinder, said control chamber having its lower endspaced from the bottom of said oil-containing chamber and having a valvechamber in its lower portion, a passage connecting said valve chamberwith said cylinder, an inlet at the bottom of said valve chamberconnecting the latter with said oilcontaining chamber, aspring-controlled valve within saidvalve chamber closing said inlet, avalve-controlled relief passage extending from said valve chamber to theu per end of said control chamber, a sleeve-hline element threaded intothe wall of said valve chamber in line with the passage between thelatter and said cylinder and having its inner end opening into saidvalve chamber and its outer portion projecting into said oil-containingchamber and provided with diametrically opposite slots opening from theouter end thereof inwardly, a stuing box in the wall of said casinalined with said sleeve-like element, an adjusting valve threadedthrough said stuffing box and having an unthreaded cylindrical portionat its inner end fittedl into said sleeve-like element and terminatingat any delinitely xed point with respect to the inner ends of saidslots.

8. A relief device for a shock absorber,

comprising a passage having a plurality of different diameters providingoppositely-disposed shoulders within said passage, a relief valve havinga body portion and an outstanding flange provided with a notch andbearing against one of said shoulders, a spring within said passagebearin at one end against the other of said shoul ers and at its otherend against' said outstanding flange, and means ed at its inner end, avalve-stem guide-sleeve screw-threaded into the inner end of saidpassage, a valve having a cylindrical portion fitted into said guidesleeve and having an outstanding flange provided with an openingtherethrough, a sprlng bearing at one end against said inwardly-facingshoulder and at its other end against said flange, and cooperating meansbetween said valve and said guide sleeve whereby an oil passage isprovided between the two when said valve is the capacity thereof inproportion to the movement of said valve outwardly against the action ofsaid spring.

l0. ln a shock absorber, a relief device comprising a passage restrictedat one end to provide an inwardly-facing shoulder and having its otherend screw-threaded, a valve stem guide sleeve threaded into thescrewythreaded end of said passage and having a slot extending from itsouter end inwardly, a cylindrical valve fitted into said guide sleeveand having an outstanding flange bearing against the outer end thereofto close the outer end of said slot, said flange having an openingtherethrough, said valve normally covering said slot, and a springacting against said valve to keep said flange in contact with the outerend of said guide sleeve, said valve being adapted to be moved againstthe action of said spring to uncover said slot in proportion to therange of movement of said valve.

il. A shock absorber, comprising a casing having an oilcontainingchamber, a cylinder, and a'wall separating said chamber from saidcylinder and provided with an exten-sion projecting into saidoil-containing chamber and serving as a control chamber for controllingthe flow of fluid from and to said oil-containing chamber, said controlchamber having a longitudinal passage therethrough reduced in diameteralong its upper portion and threaded at its lower portion, a valve seatthreaded into said threaded lower portion, a transverse passageconnecting the larger portion of said longitudinal passage with saidcylinder, a relief valve in the smaller portion of said longitudinalpassage, a valve seated against said valve seat, a spring tending tohold said valve against said Valve seat, and means connecting the largerportion of said longitudinal passage with said oil-containing chamberincluding a sleeve-like member extending into said oil-containingchamber and opening with one end into said longitudinal passage, saidsleeve-like member having slots at diametrically opposite pointsextending inwardly from the outer end thereof, and an adjustable valveextending from the exterior of said casing into said sleeve-like memberand uncovering definitely vdetermined portions of said slots at theinner end thereof to provide restricted oil passages through saidsleeve-like member.

12. A 'shock absorber, comprising a casing having anoil-containingchamber and a cylinder, a plunger within said cylinder, avalvecontrolled passage leading from said oil-containing .chamber tosaid cylinder, a sleevelike element screw-threaded with one end into thewall between said oil-containing chamber and said cylinder, saidsleeve-like element having its inner end connected with saidvalve-controlled passage between the valve thereof and said cylinder andextending into said oil-containing chamber, said sleeve-like ADOLlPl-IW. F. MANZEL.

